Power Pedestal Connections
We read an online RV newsletter that comes out each Saturday. Electricity is often a topic of discussion. Today there was a survey to try to tell what percent of readers have experienced some sort of ...
Forum Discussion
I am trying to find a way to simplify standard wiring of electrical circuits. I am probably not qualified to be and instructor but I am qualified to wire electrical circuits. I may just end up making if more confusing and complicated.
I posted a picture diagram above that shows main and sub panel wiring. That probably did not make it clear enough so I will try to split out the diagram into two separate pictures below to show both the main panel and the sub panel. The idea here being that the “sub panel” will represent a pedestal in an RV park.
First picture is the complete diagram showing both the main and sub panels. I then split the left side of that picture which is the main panel – and the right side of the picture which is the sub panel.
MAIN AND SUB PANEL
Click For Full-Size Image.Main split
In the main panel you will see the different wires and the colors typically found in electrical panels. At the upper left the sort of half circular heavy black lines represent the transformer up on the incoming power pole – or the newer type found on the ground when all wiring is done underground.
From the transformer we see three colors – red – white – black. WHITE IS ALWAYS NEUTRAL. BLACK AND/OR RED ARE ALWAYS HOT. Unfortunately in Mexico we can find any colors going anywhere and even all wires being the same color.
MAIN PANEL DIAGRAM SPLIT
Click For Full-Size Image.
To the side we see a green wire – this represents ground but in most panels these days ground will be a bare copper wire.
The black and red are shown going to the main breaker. The diagram is not the best as they use grey as for many things. There are two sets of lines below the main breaker. These lines are meant to be metal strips that are connected to the main breaker – red to the left – black to the right. Circuit breakers are mounted to these strips which connects power to the breakers.
The white wire is shown connecting to another vertical grey line with circular sort of dots which are meant to represent screws. This is called a buss. Another grey line crosses vertically to the right side of the panel – this represents and metal bar that connects to another buss that is also vertical with dots for screws.
The green wire on the left is the ground wire and is shown as being outside the panel and pointing down with sort of arrows – this represents ground and the arrows mean this goes to a grounding rod or some other approved method of grounding.
If you trace out both the white and the green lines you will see they are both connected to the vertical buss in the main panel. This is what we mean by the “same electrical point”. No matter how you call it these two are now electrically connected throughout the system. They are the same.
We can only assume the two yellow round balls at the bottom represent lightbulbs or any other appliance connected to the circuit. The grey rectangle with the white box is supposed to be a light switch or any on/off switch for whatever might be connect to these circuits. It is just a rough idea of what a simple basic circuit and panel might look like. This is not meant to be exact.
Now note the black and red wires coming from a breaker in the main panel and going over to the sub panel. These are connected to a breaker with a set of connected switches represented by the white sort of stubby letter I or sideways letter H – meaning these are two separate circuits but they switch from a mechanically connected breaker – they are not electrically connected. This circuits takes both legs of the incoming hot circuits to the sub panel.
We also see both a green and a white wire coming from the main panel buss to the sub panel.
Now look at the sub panel diagram I split out from the original diagram. Note the red and black go to a new main breaker in this sub panel. Note also that the white and green wires now go to totally separate buss strips and are not connected in any way.
SUB PANEL DIAGRAM SPLIT
Click For Full-Size Image.
If we wanted to take this to a higher level of safety we could pound another ground rod in next to our pedestal and connect that rod to the ground buss – BUT NOT TO THE NEUTRAL buss.
If everything is done correctly according to the electrical code and this very simple and basic wiring diagram then you should get the exact same voltage reading if you test from either hot (red or black) to either ground or neutral. If you test from black to red you should get somewhere around 240 volts instead of the 120 volts you would get if you test black or red to ground or neutral. It is possible that you will not see 120 volts – you could see 127 or 113 – or anywhere in between. If you test black to red you may not get 240 – but chances are you are not going to see a lot of 240 connections in Mexico. If you do you might see something like 254 since the standard voltage in Mexico is usually 127.
If you measure / test voltage on a circuit and you do not see the same voltage from hot to either ground or neutral then there is something wrong somewhere in your circuit. One possibility could be wires between the main panel and the sub panel – either the neutral or the ground wire could be the incorrect size wire and not capable of carrying the necessary current. Something is wrong somewhere because neutral and ground are the same electrical point in the main panel so should always show the same exact voltage.
I posted a picture diagram above that shows main and sub panel wiring. That probably did not make it clear enough so I will try to split out the diagram into two separate pictures below to show both the main panel and the sub panel. The idea here being that the “sub panel” will represent a pedestal in an RV park.
First picture is the complete diagram showing both the main and sub panels. I then split the left side of that picture which is the main panel – and the right side of the picture which is the sub panel.
MAIN AND SUB PANEL
In the main panel you will see the different wires and the colors typically found in electrical panels. At the upper left the sort of half circular heavy black lines represent the transformer up on the incoming power pole – or the newer type found on the ground when all wiring is done underground.
From the transformer we see three colors – red – white – black. WHITE IS ALWAYS NEUTRAL. BLACK AND/OR RED ARE ALWAYS HOT. Unfortunately in Mexico we can find any colors going anywhere and even all wires being the same color.
MAIN PANEL DIAGRAM SPLIT
To the side we see a green wire – this represents ground but in most panels these days ground will be a bare copper wire.
The black and red are shown going to the main breaker. The diagram is not the best as they use grey as for many things. There are two sets of lines below the main breaker. These lines are meant to be metal strips that are connected to the main breaker – red to the left – black to the right. Circuit breakers are mounted to these strips which connects power to the breakers.
The white wire is shown connecting to another vertical grey line with circular sort of dots which are meant to represent screws. This is called a buss. Another grey line crosses vertically to the right side of the panel – this represents and metal bar that connects to another buss that is also vertical with dots for screws.
The green wire on the left is the ground wire and is shown as being outside the panel and pointing down with sort of arrows – this represents ground and the arrows mean this goes to a grounding rod or some other approved method of grounding.
If you trace out both the white and the green lines you will see they are both connected to the vertical buss in the main panel. This is what we mean by the “same electrical point”. No matter how you call it these two are now electrically connected throughout the system. They are the same.
We can only assume the two yellow round balls at the bottom represent lightbulbs or any other appliance connected to the circuit. The grey rectangle with the white box is supposed to be a light switch or any on/off switch for whatever might be connect to these circuits. It is just a rough idea of what a simple basic circuit and panel might look like. This is not meant to be exact.
Now note the black and red wires coming from a breaker in the main panel and going over to the sub panel. These are connected to a breaker with a set of connected switches represented by the white sort of stubby letter I or sideways letter H – meaning these are two separate circuits but they switch from a mechanically connected breaker – they are not electrically connected. This circuits takes both legs of the incoming hot circuits to the sub panel.
We also see both a green and a white wire coming from the main panel buss to the sub panel.
Now look at the sub panel diagram I split out from the original diagram. Note the red and black go to a new main breaker in this sub panel. Note also that the white and green wires now go to totally separate buss strips and are not connected in any way.
SUB PANEL DIAGRAM SPLIT
If we wanted to take this to a higher level of safety we could pound another ground rod in next to our pedestal and connect that rod to the ground buss – BUT NOT TO THE NEUTRAL buss.
If everything is done correctly according to the electrical code and this very simple and basic wiring diagram then you should get the exact same voltage reading if you test from either hot (red or black) to either ground or neutral. If you test from black to red you should get somewhere around 240 volts instead of the 120 volts you would get if you test black or red to ground or neutral. It is possible that you will not see 120 volts – you could see 127 or 113 – or anywhere in between. If you test black to red you may not get 240 – but chances are you are not going to see a lot of 240 connections in Mexico. If you do you might see something like 254 since the standard voltage in Mexico is usually 127.
If you measure / test voltage on a circuit and you do not see the same voltage from hot to either ground or neutral then there is something wrong somewhere in your circuit. One possibility could be wires between the main panel and the sub panel – either the neutral or the ground wire could be the incorrect size wire and not capable of carrying the necessary current. Something is wrong somewhere because neutral and ground are the same electrical point in the main panel so should always show the same exact voltage.
